The present invention relates to a process for the delignification of lignocellulose. More particularly, this invention relates to a process for delignification in which the pulping medium is a mixture of water and a 2-oxazolidinone or a 2-imidazolidinone.
There are many known procedures which may be used to delignify wood. Such procedures generally require acidic or alkaline reaction media. An acidic medium, such as that used in the sulfite process, usually causes hydrolysis of alpha-cellulose and further is disadvantageous in that the lignin is obtained as a highly modified sulfonate. An alkaline reaction medium, such as that used in the kraft and soda processes, usually causes some destruction of hemicellulose and converts the lignin to sodium salts of organic acids which possess value mainly as fuel. Additionally, the kraft process is very capital and energy intensive, partially due to the sulfurous wastes it generates. Thus, presently used large-scale delignification processes have known shortcomings.
Heretofore, a method for the delignification of wood using substituted 2-oxazolidinones or 2-imidazolidinones has not been disclosed.